Cancers in children occur much less often and are different than in adults. Cancer in children usually grows in different types of body tissue. The most common sites of cancer in adults are skin, breast, prostate, lung, and colon. For children, cancers of the blood and bone marrow, lymph tissue, brain, nervous system, muscles, kidneys, and bone are most common. Cancer in children tends to respond better than cancer in adults to treatment.

Causes of Childhood Cancer

Many parents wonder what caused their child’s cancer. They may fear that something they did or did not do caused the disease. As far as we know, nothing that you or your child did caused or could have prevented the cancer. We know that cancer is not contagious. You cannot catch cancer from another person. Scientists are working to find the causes of cancer in children. For now, we do not know the exact cause of most childhood cancers. Only a few childhood cancers are hereditary (passed on from parent to child).

Childhood acute lymphoblastic leukemia (also called acute lymphocytic leukemia or ALL) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated. It is the most common type of cancer in children.

In ALL, too many stem cells develop into lymphoblasts and do not mature to become lymphocytes. These lymphoblasts are called leukemia cells. The leukemia cells do not work like normal lymphocytes and are not able to fight infection very well. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.

There are different subgroups of ALL based on the following:

Whether the type of blood cell that is affected looks more like a B lymphocyte or a T lymphocyte.
The age of the child at diagnosis. For example, whether the child is younger than one year, one year to 10 years old, or older than 10 years (teenager).
Whether there are certain changes in the chromosomes. Philadelphia chromosome -positive ALL is one type of chromosome change that may occur.